Save/LoadLastRunWindowBounds: also save DpiWindowSizeFactor / restore…

… size with DPI handling
pthom · Jul 5, 2024 · 1a53360 · 1a53360
1 parent 004a648
commit 1a53360
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Showing 2 changed files with 47 additions and 4 deletions.
diff --git a/src/hello_imgui/internal/backend_impls/abstract_runner.cpp b/src/hello_imgui/internal/backend_impls/abstract_runner.cpp
@@ -703,6 +703,7 @@ void AbstractRunner::Setup()
             Impl_Select_Gl_Version();
     #endif
 
+    SetupDpiAwareParams();
     PrepareWindowGeometry();
 
     auto fnRenderCallbackDuringResize = [this]()
@@ -729,8 +730,6 @@ void AbstractRunner::Setup()
 
     Impl_SetWindowIcon();
 
-    SetupDpiAwareParams();
-
     // This should be done before Impl_LinkPlatformAndRenderBackends()
     // because, in the case of glfw ImGui_ImplGlfw_InstallCallbacks
     // will chain the user callbacks with ImGui callbacks;

diff --git a/src/hello_imgui/internal/hello_imgui_ini_settings.cpp b/src/hello_imgui/internal/hello_imgui_ini_settings.cpp
@@ -173,11 +173,13 @@ namespace HelloImGui
 
         void SaveLastRunWindowBounds(const std::string& iniPartsFilename, const ScreenBounds& windowBounds)
         {
+            auto& dpiAwareParams = HelloImGui::GetRunnerParams()->dpiAwareParams;
             IniParts iniParts = IniParts::LoadFromFile(iniPartsFilename);
 
             ini::IniFile iniFile;
             iniFile["AppWindow"]["WindowPosition"] = IntPairToString(windowBounds.position);
             iniFile["AppWindow"]["WindowSize"] = IntPairToString(windowBounds.size);
+            iniFile["AppWindow"]["DpiWindowSizeFactor"] = dpiAwareParams.dpiWindowSizeFactor;
             std::string iniContent = iniFile.encode();
 
             iniParts.SetIniPart("AppWindow", iniContent);
@@ -206,23 +208,65 @@ namespace HelloImGui
             ScreenBounds screenBounds;
             bool failed = false;
 
+            if (iniFile.find("AppWindow") == iniFile.end())
+                return std::nullopt;
+            auto & appWindowSection = iniFile["AppWindow"];
+
+            // Read Window Position
             {
-                auto strValue = iniFile["AppWindow"]["WindowPosition"].as<std::string>();
+                if (appWindowSection.find("WindowPosition") == appWindowSection.end())
+                    return std::nullopt;
+                auto strValue = appWindowSection["WindowPosition"].as<std::string>();
                 auto intPair = StringToIntPair(strValue);
                 if (intPair[0] >= 0)
                     screenBounds.position = intPair;
                 else
                     failed = true;
             }
+            // Read Window Size
             {
-                auto strValue = iniFile["AppWindow"]["WindowSize"].as<std::string>();
+                if (appWindowSection.find("WindowSize") == appWindowSection.end())
+                    return std::nullopt;
+                auto strValue = appWindowSection["WindowSize"].as<std::string>();
                 auto intPair = StringToIntPair(strValue);
                 if (intPair[0] >= 0)
                     screenBounds.size = intPair;
                 else
                     failed = true;
             }
 
+            // Read DPI Window Size Factor
+            // If needed, change the size to match the current DPI versus the DPI when the size was saved
+            // (we want the window to "look" as big as it was when saved, even if the DPI has changed,
+            //  or if we are on a different monitor / computer / OS)
+            {
+                // DpiWindowSizeFactor was added late, so it may not be present in the ini file
+                if (appWindowSection.find("DpiWindowSizeFactor") != appWindowSection.end())
+                {
+                    float dpiWindowSizeFactor_WhenSaved = iniFile["AppWindow"]["DpiWindowSizeFactor"].as<float>();
+                    bool isDpiSane = (dpiWindowSizeFactor_WhenSaved >= 0.1) || (dpiWindowSizeFactor_WhenSaved <= 10.0);
+                    if (isDpiSane)
+                    {
+                        float dpiWindowSizeFactor_Now = HelloImGui::GetRunnerParams()->dpiAwareParams.dpiWindowSizeFactor;
+                        float ratio = dpiWindowSizeFactor_Now / dpiWindowSizeFactor_WhenSaved;
+                        if (ratio != 1.f)
+                        {
+                            auto applyRatio = [](int v, float ratio) -> int
+                            {
+                                return static_cast<int>(static_cast<float>(v) * ratio);
+                            };
+                            screenBounds.position[0] = applyRatio(screenBounds.position[0], ratio);
+                            screenBounds.position[1] = applyRatio(screenBounds.position[1], ratio);
+                            screenBounds.size[0] = applyRatio(screenBounds.size[0], ratio);
+                            screenBounds.size[1] = applyRatio(screenBounds.size[1], ratio);
+                        }
+                    }
+                }
+            }
+            {
+
+            }
+
             if (failed)
                 return std::nullopt;
             else